Additives and Crystallization Processes: From Fundamentals to Applications / Edition 1

Additives and Crystallization Processes: From Fundamentals to Applications / Edition 1

by Keshra Sangwal
     
 

ISBN-10: 0470061537

ISBN-13: 9780470061534

Pub. Date: 11/16/2007

Publisher: Wiley

Crystal growth technology involves processes for the production of crystals essential for microelectronics, communication technologies, lasers and energy producing and energy saving technology. A deliberately added impurity is called an additive and in different industries these affect the process of crystal growth. Thus, understanding of interactions between

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Overview

Crystal growth technology involves processes for the production of crystals essential for microelectronics, communication technologies, lasers and energy producing and energy saving technology. A deliberately added impurity is called an additive and in different industries these affect the process of crystal growth. Thus, understanding of interactions between additives and the crystallizing phases is important in different processes found in the lab, nature and in various industries.

This book presents a generalized description of the mechanisms of action of additives during nucleation, growth and aggregation of crystals during crystallization and has received endorsement from the President of the International Organization for Crystal Growth. It is the first text devoted to the role of additives in different crystallization processes encountered in the lab, nature and in industries as diverse as pharmaceuticals, food and biofuels.

A unique highlight of the book are chapters on the effect of additives on crystal growth processes, since the phenomena discussed is an issue of debate between researchers

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Product Details

ISBN-13:
9780470061534
Publisher:
Wiley
Publication date:
11/16/2007
Pages:
468
Product dimensions:
6.93(w) x 9.94(h) x 1.32(d)

Table of Contents

Preface xiii

1 Complexes in Solutions 1

1.1 Structure of Common Solvents 2

1.2 Structure of Pure Aqueous Electrolyte Solutions 4

1.2.1 Solvation of Electrolyte Ions in Solutions 4

1.2.2 Concentrated and Saturated Electrolyte Solutions 6

1.2.3 Formation of Aquo and Partially Aquo Complexes 8

1.3 Structure of Aqueous Electrolyte Solutions Containing Additives 10

1.4 Polyelectrolytes and Surfactants in Solutions 16

1.5 Polydentate Ligands and Molecular Additives 18

1.6 Crystal–Additive Interactions 19

References 19

2 Three-Dimensional Nucleation and Metastable Zone Width 21

2.1 Driving Force for Phase Transition 22

2.2 Three-Dimensional Nucleation of Crystals 25

2.2.1 Three-Dimensional Nucleation Rate 25

2.2.2 Three-Dimensional Heterogeneous Nucleation 30

2.3 Metastable Zone Width 35

2.4 Nucleation and Transformation of Metastable Phases 38

2.4.1 Crystallization of Metastable Phases 38

2.4.2 Overall Crystallization 41

2.5 Induction Period for Crystallization 47

2.6 Effects of Additives 52

2.6.1 Solubility 52

2.6.2 Three-Dimensional Nucleation Rate 56

2.6.3 Metastable Zone Width 56

References 62

3 Kinetics and Mechanism of Crystal Growth: An Overview 65

3.1 Crystal Growth as a Kinetic Process 66

3.2 Types of Crystal–Medium Interfaces 67

3.3 Roughening of Steps and Surfaces 69

3.3.1 Thermodynamic Roughening and the Surface Entropy Factor 70

3.3.2 Kinetic Roughening 72

3.4 Growth Kinetics of Rough Faces 73

3.5 Growth Kinetics of Perfect Smooth Faces 75

3.6 Growth Kinetics of Imperfect Smooth Faces 78

3.6.1 Surface Diffusion and Direct Integration Models 78

3.6.2 Bulk Diffusion Models 80

3.6.3 Growth by a Group of Cooperating Screw Dislocations 82

3.6.4 Preferential Growth at Edge Dislocations 84

3.7 Effect of Foreign Substances on Growth Kinetics 85

3.7.1 Some General Considerations 87

3.7.2 Growth Kinetics by Heterogeneous Two-Dimensional Nucleation 90

3.8 Real Crystal Growth Mechanisms 96

3.8.1 Structure of Interfacial Layer 96

3.8.2 Sources of Growth Steps 100

3.9 Techniques for Studying Growth Kinetics 104

References 105

4 Effect of Impurities on Crystal Growth Kinetics 109

4.1 Mobile and Immobile Impurities 109

4.2 Surface Coverage and Adsorption Isotherms 112

4.2.1 Adsorption Isotherms 113

4.2.2 Changes in Surface Free Energy by Adsorption of Impurities 115

4.3 Kinetic Models of Impurity Adsorption 115

4.3.1 Earlier Models 115

4.3.2 Velocity of Curved Steps 116

4.3.3 Impurity Adsorption at Kinks in Steps: Kubota–Mullin Model 118

4.3.4 Impurity Adsorption at Surface Terrace: Cabrera–Vermilyea Model 119

4.3.5 Effectiveness Factor for Impurity Adsorption 121

4.3.6 Adsorption of Two Competing Impurities 124

4.4 Confrontation of Impurity Adsorption Mechanisms with Experimental Data 127

4.5 Time-Dependent Impurity Adsorption 132

4.6 Growth Kinetics in the Presence of Impurities 136

4.6.1 Basic Kinetic Equations 136

4.6.2 Time Dependence of Face Displacement 141

4.6.3 Dependence of Kinetic Coefficient for Step Motion on Impurity Concentration 142

4.7 Tapering of KDP-Type Crystals 143

4.8 Growth-Promoting Effects of Impurities 146

4.8.1 Decrease in Step Free Energy and Roughening of Steps 147

4.8.2 Formation of Surface Macroclusters 152

4.9 Impurity Adsorption on Rough Faces 157

4.10 Formation of Two-Dimensional Adsorption Layer 158

4.11 Interactions Between Additives and Crystal Interface 160

4.11.1 Nature of Impurity–Crystal Interactions 160

4.11.2 Chemical Aspects of Impurity–Crystal Interactions 166

4.12 Tailor-Made Additives 172

References 174

5 Dead Supersaturation Zone and Threshold Supersaturations for Growth 177

5.1 Origin of Threshold Supersaturations for Growth 179

5.1.1 Basic Kinetic Equations 179

5.1.2 Three Different Distances Between Impurity Particles 182

5.2 Determination of Threshold Supersaturations from v (σ) and R (σ) Data 184

5.2.1 Relationship Between the Model Involving Cooperating Spirals and the Power-Law Approach 185

5.2.2 Relationship Between the Power-Law Approach and an Empirical Expression with Corrected Supersaturation 185

5.2.3 Determination of σ∗ 186

5.3 Dependence of Threshold Supersaturations on Impurity Concentration: Basic Theoretical Equations and Linear Approximations 187

5.4 Confrontation of Theoretical Equations with Experimental Data 190

5.4.1 Impurity Adsorption at Kinks and Surface Terrace 190

5.4.2 Threshold Supersaturations and Impurity Adsorption Isotherms 193

5.5 Impurity Adsorption and Solution Supersaturation 197

5.6 Dependence of Ratios σd/σ∗ and σ∗/σ∗∗ on ci 198

References 202

6 Mineralization in Natural and Artificial Systems 205

6.1 Biomineralization as a Process 205

6.1.1 Structure and Composition of Biominerals 205

6.1.2 Humans and Animals 206

6.1.3 Plants 209

6.1.4 Mollusk Shells and Avian Eggshells 211

6.2 Pathological Mineralization 216

6.3 Effect of Biologically Active Additives on Crystallization Processes 222

6.3.1 Overall Precipitation Kinetics 222

6.3.2 Overall Growth Kinetics 230

6.3.3 Phases and Polymorphs of Crystallizing Calcium Salts 242

6.3.4 Transformation of Metastable Phases 247

6.4 Scale Formation and Salt Weathering 258

References 262

7 Morphology and Size Distribution of Crystals 265

7.1 Growth Morphology of Crystals 266

7.1.1 General Concepts 266

7.1.2 Effect of Additives on Surface Morphology 273

7.1.3 Effect of Solvent on Crystal Morphology 275

7.1.4 Growth Morphodroms 276

7.2 Ostwald Ripening and Crystal Size Dispersion 282

7.3 Crystal Size Distribution 284

7.3.1 Population Balance Approach 285

7.3.2 Balanced Nucleation-Growth Approach 289

7.3.3 Approach Based on Law of Proportionate Effect 291

7.3.4 Effect of Additives on Crystal Size Distribution 295

7.4 Control of Shape and Size of Particles 298

7.4.1 Growth-Directed Synthesis 298

7.4.2 Template-Directed Synthesis 307

7.5 Biological Tissue Engineering 311

References 314

8 Additives and Crystallization Processes in Industries 319

8.1 Pharmaceutical Industry 320

8.1.1 Nucleation, Growth and Morphology of Drug Crystals 321

8.1.2 Preparation and Size Distribution of Drug Particles 324

8.2 Petroleum Industry 330

8.2.1 Some Basic Concepts 331

8.2.2 Crystallization Behavior of Linear Long-Chain n-Alkanes 332

8.2.3 Biodiesels and their Crystallization Behavior 338

8.3 Food Industry 348

8.3.1 Some Basic Concepts 351

8.3.2 Crystallization of Food Fats in the Bulk 356

8.3.3 Crystallization of Polymorphs 361

8.3.4 Crystallization of Fats and Oils in Emulsion Droplets 366

8.3.5 Number of Nucleation Centers and Overall Crystallization in Emulsion Systems 372

References 377

9 Incorporation of Impurities in Crystals 381

9.1 Types of Impurity Incorporation and the Segregation Coefficient 382

9.2 Equilibrium Segregation Coefficient 386

9.2.1 Binary Mixture Approach 386

9.2.2 Thermodynamic Approach 388

9.2.3 Theoretical Predictions and their Comparison with Experimental Data on Segregation Coefficient 389

9.3 Effective Segregation Coefficient 396

9.3.1 Volume Diffusion Model 396

9.3.2 Diffusional Relaxation Approach 397

9.3.3 Statistical Selection Approach 401

9.3.4 Surface Adsorption Approach 402

9.4 Relationship Between Effective Segregation Coefficient and Face Growth Rate 410

9.5 Threshold Supersaturation for Trapping of Impurities During Growth 413

9.6 Effective Segregation Coefficient and Internal Stresses Caused by Impurities 416

References 418

List of Symbols 421

Subject Index 427

Author Index 437

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